阅读说明：本技术 基于矢量控制系统的电机控制方法、系统及存储介质 (Motor control method and system based on vector control system and storage medium ) 是由 王得利 于 2018-07-05 设计创作，主要内容包括：本发明提供了一种基于矢量控制系统的电机控制方法、基于矢量控制系统的电机控制系统以及一种计算机可读存储介质。其中,方法包括：在速度环开环时,向永磁同步电机的q轴注入第一预设电流并维持第一预设时长；控制永磁同步电机的转子按照预设加速度加速至预设转速并运行第二预设时长,以及计算永磁同步电机的d轴的假定转子磁链角度；向q轴和d轴注入第二预设电流,并实时计算永磁同步电机的转子磁链角度；根据假定转子磁链角度和转子磁链角度判断是否控制速度环由开环切换至闭环。通过假定转子磁链角度与转子磁链角度判断速度环的切换时机,避免了直接切换容易出现的切换过程中永磁同步电机转速及电流振荡甚至启动失败的情况,提高了启动几率。(The invention provides a motor control method based on a vector control system, a motor control system based on the vector control system and a computer readable storage medium. The method comprises the following steps: when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining a first preset time; controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating a supposed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor; injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time; and judging whether to control the speed ring to be switched from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle. The switching time of the speed ring is judged by assuming the rotor flux linkage angle and the rotor flux linkage angle, so that the conditions of the rotation speed and current oscillation of the permanent magnet synchronous motor and even the starting failure in the switching process which is easy to occur in the direct switching process are avoided, and the starting probability is improved.)

1. A motor control method based on a vector control system is applied to a permanent magnet synchronous motor, wherein the vector control system at least comprises a speed loop and a current loop, and is characterized by comprising the following steps:

when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining the first preset time;

controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor;

injecting a second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time;

and judging whether to control the speed ring to be switched from an open loop to a closed loop or not according to the assumed rotor flux linkage angle and the rotor flux linkage angle.

2. The motor control method based on the vector control system according to claim 1,

the calculating of the assumed rotor flux linkage angle of the d-axis of the permanent magnet synchronous motor specifically includes:

and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time.

3. The motor control method based on the vector control system according to claim 2,

the second preset current is specifically calculated by the following formula:

where, delta is a function of time,t is a third preset duration for which δ is changed from 90 ° to 0 °.

4. The method of claim 3, wherein the motor control method is based on a vector control system

The specifically determining whether to control the speed ring to be switched from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle includes:

calculating an angle difference between the assumed rotor flux linkage angle and the rotor flux linkage angle;

judging whether the angle difference value is in a first preset range or not, and controlling the speed ring to be switched from an open loop to a closed loop when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

5. The motor control method based on the vector control system according to claim 3,

the specifically determining whether to control the speed ring to be switched from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle includes:

calculating an angle difference between the assumed rotor flux linkage angle and the rotor flux linkage angle;

carrying out low-pass filtering processing on the angle difference;

carrying out angle compensation on the low-pass filtering processing result;

judging whether the angle compensation result is in a second preset range or not, and controlling the speed ring to be switched from an open loop to a closed loop when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

6. The motor control method based on the vector control system according to claim 4 or 5,

when a second preset current is input to the q axis and the d axis and the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time, the method further comprises the following steps:

and acquiring the current of the d axis and the current of the q axis, outputting the current of the q axis to a PI controller of the speed loop, and outputting the current of the d axis to an id instruction controller of the current loop.

7. The vector control system-based motor control method according to any one of claims 1 to 6,

after the controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time length, and calculating an assumed rotor flux linkage angle of a d-axis of the permanent magnet synchronous motor, before inputting a second preset current to the q-axis and the d-axis and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, the method further includes:

and controlling the rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotating speed.

8. The motor control method based on the vector control system according to claim 7,

the low-pass filtering processing on the angle difference is specifically calculated by the following formula:

wherein, theta_{err_lpf}For the angle difference after the low-pass filtering process, τ is the time constant of the low-pass filtering, s is the complex variable in the Laplace transform, and θ_errIs the angular difference without low pass filtering.

9. The motor control method based on the vector control system according to claim 7,

the angle compensation of the low-pass filtering processing result is specifically calculated by the following formula:

wherein, theta_{err_cri}For the angle compensation result, τ is the time constant of the low-pass filtering, T is a third preset time period for changing δ from 90 ° to 0 °, and θ_{err_lpf}Is the angle difference after the low-pass filtering process.

10. A motor control system based on a vector control system is applied to a permanent magnet synchronous motor, wherein the vector control system at least comprises a speed loop and a current loop, and is characterized by comprising the following components:

a memory for storing a computer program;

a processor for executing the computer program to:

when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining the first preset time;

controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor;

injecting a second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time;

and judging whether to control the speed ring to be switched from an open loop to a closed loop or not according to the assumed rotor flux linkage angle and the rotor flux linkage angle.

11. The motor control system of claim 10, wherein the processor is specifically configured to execute the computer program to:

and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time.

12. The motor control system of claim 11, wherein the second predetermined current is calculated by the following equation:

where, delta is a function of time,

13. The motor control system of claim 12, wherein the processor is specifically configured to execute the computer program to:

calculating an angle difference between the assumed rotor flux linkage angle and the rotor flux linkage angle;

judging whether the angle difference value is in a first preset range or not, and controlling the speed ring to be switched from an open loop to a closed loop when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

14. The motor control system of claim 12, wherein the processor is specifically configured to execute the computer program to:

calculating an angle difference between the assumed rotor flux linkage angle and the rotor flux linkage angle;

carrying out low-pass filtering processing on the angle difference;

carrying out angle compensation on the low-pass filtering processing result;

judging whether the angle compensation result is in a second preset range or not, and controlling the speed ring to be switched from an open loop to a closed loop when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

15. The motor control system of claim 13 or 14, wherein the processor is further configured to execute the computer program to:

and acquiring the current of the d axis and the current of the q axis, outputting the current of the q axis to a PI controller of the speed loop, and outputting the current of the q axis to an id instruction controller of the current loop.

16. The motor control system of any of claims 10-15, wherein the processor is further configured to execute the computer program to:

and controlling the rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotating speed.

17. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the motor control method according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of permanent magnet synchronous motor control, in particular to a motor control method based on a vector control system, a motor control system based on the vector control system and a computer readable storage medium.

Background

The existing permanent magnet synchronous motor controlled by a speed sensor is widely applied to various fields, the common mode for controlling the starting of the permanent magnet synchronous motor is to open a speed ring and a current ring to close the speed ring, control the rotation of a rotor of the permanent magnet synchronous motor until the rotor and an angle observer are stable, and then switch the speed ring to the closed ring, however, the rotor speed and the current of the permanent magnet synchronous motor easily appear to vibrate when the speed ring is switched to the closed ring from an open-loop state, and the condition of failed starting appears.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art or the related art.

To this end, a first aspect of the present invention is to provide a motor control method based on a vector control system.

In a second aspect of the present invention, a motor control system based on a vector control system is provided.

A third aspect of the present invention is to provide a computer-readable storage medium.

In view of the above, according to a first aspect of the present invention, there is provided a motor control method based on a vector control system, applied to a permanent magnet synchronous motor, wherein the vector control system at least comprises a speed loop and a current loop, and wherein the motor control method based on the vector control system comprises: when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining a first preset time; controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating a supposed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor; injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time; and judging whether to control the speed ring to be switched from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle.

The invention provides a motor control method based on a vector control system, which comprises the steps of injecting a first preset current into a q axis of a permanent magnet motor when a speed loop is opened, continuing for a first preset time, controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle of a d axis while accelerating to the preset rotating speed; and injecting second preset current into the q axis and the d axis, calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, judging whether to control the speed ring to be switched from an open loop to a closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, judging the switching time of the speed ring by the assumed rotor flux linkage angle and the rotor flux linkage angle, avoiding the rotor speed and current oscillation of the permanent magnet synchronous motor after switching which is easy to occur in direct switching, and improving the starting probability due to the starting failure.

In addition, according to the motor control method based on the vector control system in the above technical solution provided by the present invention, the following additional technical features may be further provided:

in the foregoing technical solution, preferably, the calculating an assumed rotor flux linkage angle of the d-axis of the permanent magnet synchronous motor specifically includes: and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time.

In the technical scheme, the assumed rotor flux linkage angle of the d-axis is obtained by integrating the acceleration to the preset rotation speed within a second preset time according to the preset acceleration, wherein the second preset time, the preset acceleration and the preset rotation speed are reasonably set according to the starting requirement of the permanent magnet synchronous motor.

In any of the above technical solutions, preferably, the second preset current is calculated by the following formula:

where, delta is a function of time,

t is a third preset duration for which δ is changed from 90 ° to 0 °.

In the technical scheme, the second preset current continuously changes according to time, so that the input current of the permanent magnet synchronous motor is continuously adjusted until the switching time of the speed loop is judged by assuming the rotor flux angle and the rotor flux angle, the conditions that the permanent magnet synchronous motor outputs the speed rotor rotating speed after switching and the current in the switching process is vibrated, the starting failure occurs and the starting probability is improved, which are easy to occur in direct switching are avoided.

In any of the above technical solutions, preferably, the determining whether to control the speed loop to switch from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle specifically includes: calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle; judging whether the angle difference value is in a first preset range, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In the technical scheme, the angle difference between the assumed rotor flux linkage angle and the rotor flux linkage angle is calculated, when the angle difference value is in a first preset range, the time for switching the speed ring is considered to be met, the speed ring is controlled to be switched from an open ring to a closed ring, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time again, and judging whether to control the process of switching the speed ring from open loop to closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, the assumed rotor flux linkage angle and the observed rotor flux linkage angle are limited within a certain range by setting a variation range of an angle difference value between the assumed rotor flux linkage angle and the rotor flux linkage angle and utilizing a first preset range, thereby reducing the conditions of output speed rotor rotation speed in the switching process of the speed ring and current oscillation in the switching process and starting failure, the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the first preset range.

In any of the above technical solutions, preferably, the determining whether to control the speed loop to switch from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle specifically includes: calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle; carrying out low-pass filtering processing on the angle difference; carrying out angle compensation on the low-pass filtering processing result; judging whether the angle compensation result is in a second preset range or not, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In the technical scheme, an angle difference value of an assumed rotor flux linkage angle and a rotor flux linkage angle is calculated, low-pass filtering and angle compensation processing are carried out on the angle difference value, interference waveforms existing in the rotor flux linkage angle obtaining process are eliminated, meanwhile, angle compensation is utilized to process the low-pass filtering processing result, the problem that angle deviation occurs after the calculation is finished, so that the rotor rotating speed additionally generated in the speed ring switching process and current oscillation in the switching process are caused, starting failure is caused, when the angle compensation result is in a second preset range, the time of switching according with the speed ring is considered, the speed ring is controlled to be switched from an open loop to a closed loop, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time again, and whether the speed ring is controlled to be switched from the open loop to the closed loop or not is judged according to the assumed rotor flux linkage angle and the rotor flux linkage angle, the change range of the angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle is set, the assumed rotor flux linkage angle and the rotor flux linkage angle obtained by observation are limited within a certain range by utilizing the second preset range, the output speed rotor rotating speed in the speed ring switching process and the current oscillation in the switching process are further reduced, the starting failure condition occurs, and the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the second preset range.

In any of the above technical solutions, preferably, when a second preset current is input to the q-axis and the d-axis and a rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time, the method further includes: and acquiring the current of the d axis and the current of the q axis, outputting the current of the q axis to a PI controller of a speed loop, and outputting the current of the q axis to an id instruction controller of a current loop.

In the technical scheme, currents of a d axis and a q axis are obtained while the rotor flux linkage angle of the permanent magnet synchronous motor is calculated, the currents of the q axis are output to a PI controller of a speed ring, the currents of the q axis are output to an id instruction controller of a current ring, the current instructions when the speed ring is switched from an open loop to a closed loop are the same, and the situation that starting failure is caused by the fact that a difference value exists between the current instructions before and after switching is avoided.

In any of the above technical solutions, preferably, after controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotation speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle of the d-axis of the permanent magnet synchronous motor, before inputting a second preset current to the q-axis and the d-axis and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, the method further includes: and controlling the rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotating speed.

In the technical scheme, after the rotor of the permanent magnet synchronous motor is controlled to accelerate to the preset rotating speed according to the preset acceleration and operate for the second preset time, and the assumed rotor flux linkage angle of the d shaft of the permanent magnet synchronous motor is calculated, before the second preset current is input to the q shaft and the d shaft, and the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time, the rotor of the permanent magnet synchronous motor is controlled to operate for the fourth preset time according to the preset rotating speed so as to ensure that all parameter areas of the permanent magnet motor are stable at the preset rotating speed, errors caused by the calculation of the rotor flux linkage angle by the preset acceleration when the preset rotating speed is just reached are avoided, and the observation precision of the rotor flux linkage angle is further improved.

In any of the above technical solutions, preferably, the low-pass filtering processing on the angle difference is specifically calculated by the following formula:

wherein, theta_{err_lpf}For the angle difference after the low-pass filtering process, τ is the time constant of the low-pass filtering, s is the complex variable in the Laplace transform, and θ_errIs the angular difference without low pass filtering.

In the technical scheme, the angle difference theta after the low-pass filtering processing_{err_lpf}Directly passing through the time constant tau of the low-pass filtering, the complex variable s in the Laplace transform, the angular difference theta of the low-pass filtering_errAnd (4) calculating without complex technical process.

In any of the above technical solutions, preferably, the angle compensation for the low-pass filtering processing result is specifically calculated by the following formula:

wherein, theta_{err_cri}For the angle compensation result, τ is the time constant of the low-pass filtering, T is a third preset time period for changing δ from 90 ° to 0 °, and θ_{err_lpf}Is the angle difference after the low-pass filtering process.

In this solution, the angle compensation result θ_{err_cri}A third preset time length T for changing the time constants tau and delta from 90 DEG to 0 DEG through low-pass filtering and the angle difference theta after the low-pass filtering processing_{err_lpf}The calculation is directly carried out, and a complex technical process is not needed.

According to a second aspect of the present invention, there is provided a motor control system based on a vector control system for a permanent magnet synchronous motor, wherein the vector control system comprises at least a speed loop and a current loop, wherein the motor control system based on the vector control system comprises: a memory for storing a computer program; a processor for executing a computer program to: when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining a first preset time; controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating a supposed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor; injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time; and judging whether to control the speed ring to be switched from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle.

The invention provides a motor control system based on a vector control system, a processor executes a computer program stored in a memory to: when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet motor, continuing for a first preset time, controlling according to a maximum torque current ratio, reducing the copper consumption of a stator, controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle on a d axis while accelerating to the preset rotating speed; and injecting second preset current into the q axis and the d axis, calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, judging whether to control the speed ring to be switched from an open loop to a closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, judging the switching time of the speed ring by the assumed rotor flux linkage angle and the rotor flux linkage angle, avoiding the situation of failed start-up caused by the rotor speed and current oscillation of the permanent magnet synchronous motor output speed after switching which is easy to occur in direct switching, and improving the start-up probability.

In addition, according to the motor control system based on the vector control system in the above technical solution provided by the present invention, the following additional technical features may be further provided:

in the foregoing technical solution, preferably, the processor is specifically configured to execute a computer program to: and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time.

In the technical scheme, the assumed rotor flux linkage angle of the d-axis is obtained by integrating the acceleration to the preset rotation speed within a second preset time according to the preset acceleration, wherein the second preset time, the preset acceleration and the preset rotation speed are reasonably set according to the starting requirement of the permanent magnet synchronous motor.

In any of the above technical solutions, preferably, the processor is specifically configured to execute a computer program to: the second preset current is specifically calculated by the following formula:

where, delta is a function of time,

t is a third preset duration for which δ is changed from 90 ° to 0 °.

In the technical scheme, the second preset current continuously changes according to time, so that the input current of the permanent magnet synchronous motor is continuously adjusted until the switching time of the speed loop is judged by assuming the rotor flux angle and the rotor flux angle, the situation that the permanent magnet synchronous motor fails to start due to the fact that the rotor speed and the current of the permanent magnet synchronous motor are oscillated after switching easily occurs in direct switching is avoided, and the starting probability is improved.

In any of the above technical solutions, preferably, the processor is specifically configured to execute a computer program to: calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle; judging whether the angle difference value is in a first preset range, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In the technical scheme, the angle difference between the assumed rotor flux linkage angle and the rotor flux linkage angle is calculated, when the angle difference value is in a first preset range, the time for switching the speed ring is considered to be met, the speed ring is controlled to be switched from an open ring to a closed ring, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time again, and judging whether to control the process of switching the speed ring from open loop to closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, the assumed rotor flux linkage angle and the observed rotor flux linkage angle are limited within a certain range by setting a variation range of an angle difference value between the assumed rotor flux linkage angle and the rotor flux linkage angle and utilizing a first preset range, thereby reducing the conditions of rotor rotation speed and current oscillation in the switching process of the speed ring and starting failure, the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the first preset range.

In any of the above technical solutions, preferably, the processor is specifically configured to execute a computer program to: calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle; carrying out low-pass filtering processing on the angle difference; carrying out angle compensation on the low-pass filtering processing result; judging whether the angle compensation result is in a second preset range or not, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In the technical scheme, an angle difference value of an assumed rotor flux linkage angle and a rotor flux linkage angle is calculated, low-pass filtering and angle compensation processing are carried out on the angle difference value, interference waveforms existing in the process of obtaining the rotor flux linkage angle are eliminated, meanwhile, angle compensation is utilized to process the low-pass filtering processing result, the problem that the angle deviation occurs after the calculation is finished, so that the rotor rotating speed and current oscillation additionally generated in the process of switching a speed ring are caused, starting failure is caused, when the angle compensation result is in a second preset range, the time of switching the speed ring is considered to be in accordance with the speed ring, the speed ring is controlled to be switched from an open ring to a closed ring, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated again in real time, whether the process of switching the speed ring from the open ring to the closed ring is judged according to the assumed rotor flux linkage angle, and the change range of the angle difference value of the assumed rotor flux linkage angle and the rotor, and the assumed rotor flux linkage angle and the observed rotor flux linkage angle are limited in a certain range by utilizing the second preset range, so that the conditions of rotor rotation speed and current oscillation and starting failure in the speed ring switching process are reduced, and the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the second preset range.

In any of the above technical solutions, preferably, the processor is further configured to execute the computer program to:

and obtaining the currents of the d axis and the q axis, outputting the current of the q axis to a PI controller of a speed loop, and outputting the current of the d axis to an id instruction controller of a current loop.

In the technical scheme, currents of a d axis and a q axis are obtained while a rotor flux linkage angle of the permanent magnet synchronous motor is calculated, wherein the currents of the q axis are output to a PI controller of a speed ring, the currents of the q axis are output to an id instruction controller of a current ring, the current instructions when the speed ring is switched from an open loop to a closed loop are the same, and the situation that starting failure is caused by the fact that a difference value exists between the current instructions before and after switching is avoided.

In any of the above technical solutions, preferably, the processor is further configured to execute the computer program to: and controlling the rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotating speed.

In the technical scheme, after the rotor of the permanent magnet synchronous motor is controlled to accelerate to the preset rotating speed according to the preset acceleration and operate for the second preset time, and the assumed rotor flux linkage angle of the d shaft of the permanent magnet synchronous motor is calculated, before the second preset current is input to the q shaft and the d shaft, and the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time, the rotor of the permanent magnet synchronous motor is controlled to operate for the fourth preset time according to the preset rotating speed so as to ensure that all parameter areas of the permanent magnet motor are stable at the preset rotating speed, errors caused by the calculation of the rotor flux linkage angle by the preset acceleration when the preset rotating speed is just reached are avoided, and the observation precision of the rotor flux linkage angle is further improved.

In any of the above technical solutions, preferably, the low-pass filtering processing on the angle difference is specifically calculated by the following formula:

wherein, theta_{err_lpf}For the angle difference after the low-pass filtering process, τ is the time constant of the low-pass filtering, s is the complex variable in the Laplace transform, and θ_errIs the angular difference without low pass filtering.

In the technical scheme, the angle difference theta after the low-pass filtering processing_{err_lpf}Directly passing through the time constant tau of the low-pass filtering, the complex variable s in the Laplace transform, the angular difference theta of the low-pass filtering_errAnd (4) calculating without complex technical process.

In any of the above technical solutions, preferably, the angle compensation for the low-pass filtering processing result is specifically calculated by the following formula:

wherein, theta_{err_cri}For the angle compensation result, τ is the time constant of the low-pass filtering, T is a third preset time period for changing δ from 90 ° to 0 °, and θ_{err_lpf}Is the angle difference after the low-pass filtering process.

In this solution, the angle compensation result θ_{err_cri}A third preset time length T for changing the time constants tau and delta from 90 DEG to 0 DEG through low-pass filtering and the angle difference theta after the low-pass filtering processing_{err_lpf}The calculation is directly carried out, and a complex technical process is not needed.

According to a fourth aspect of the present invention, there is provided a computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of the method according to any one of the preceding claims.

In the computer-readable storage medium provided by the present invention, when being executed by a processor, the computer program stored thereon can implement the steps of the method according to any of the above technical solutions, so that the method has all the beneficial technical effects of the above motor control method based on the vector control system, and details are not repeated herein.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 shows a schematic flow diagram of a motor control method based on a vector control system according to an embodiment of the present invention;

FIG. 2 shows a schematic flow diagram of a motor control method based on a vector control system according to another embodiment of the present invention;

FIG. 3 shows a schematic flow diagram of a motor control method based on a vector control system according to yet another embodiment of the present invention;

FIG. 4 shows a schematic flow diagram of a motor control method based on a vector control system according to yet another embodiment of the present invention;

FIG. 5 shows a schematic flow diagram of a motor control method based on a vector control system according to yet another embodiment of the present invention;

FIG. 6 shows a schematic flow diagram of a motor control method based on a vector control system according to yet another embodiment of the present invention;

FIG. 7 shows a schematic block diagram of a motor control system based on a vector control system according to an embodiment of the present invention;

FIG. 8 shows a schematic flow diagram of a motor control method based on a vector control system according to yet another embodiment of the present invention;

FIG. 9 illustrates a block diagram of a motor control based on a vector control system in one embodiment of the present invention;

FIG. 10 is a diagram illustrating a frequency, a first predetermined current, a second predetermined current, and an angle difference according to an embodiment of the present invention.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

Embodiments of the first aspect of the present invention provide a motor control method based on a vector control system, which is applied to a permanent magnet synchronous motor, wherein the vector control system at least comprises a speed loop and a current loop.

Fig. 1 shows a schematic flow diagram of a motor control method based on a vector control system according to an embodiment of the present invention.

As shown in fig. 1, a motor control method based on a vector control system of a compressor according to an embodiment of the present invention includes:

s102, when a speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining the first preset time;

s104, controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor;

s106, injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time;

and S108, judging whether to control the speed ring to be switched from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle.

The invention provides a motor control method based on a vector control system, which comprises the steps of injecting a first preset current into a q axis of a permanent magnet motor when a speed loop is opened, continuing for a first preset time, controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle of a d axis while accelerating to the preset rotating speed; and injecting second preset current into the q axis and the d axis, calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, judging whether to control the speed ring to be switched from an open loop to a closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, judging the switching time of the speed ring by the assumed rotor flux linkage angle and the rotor flux linkage angle, avoiding the rotor speed and current oscillation of the permanent magnet synchronous motor after switching which is easy to occur in direct switching, and improving the starting probability due to the starting failure.

Fig. 2 shows a schematic flow diagram of a motor control method based on a vector control system according to another embodiment of the present invention.

As shown in fig. 2, a motor control method based on a vector control system according to another embodiment of the present invention includes:

s202, when a speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining the first preset time;

s204, controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time;

s206, injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time;

and S208, judging whether to switch the speed control ring from the open ring to the closed ring according to the assumed rotor flux linkage angle and the rotor flux linkage angle.

In this embodiment, the assumed rotor flux linkage angle of the d-axis is obtained by integrating the acceleration to the preset rotation speed according to the preset acceleration within a second preset time period, wherein the second preset time period, the preset acceleration and the preset rotation speed are reasonably set according to the starting requirement of the permanent magnet synchronous motor.

In an embodiment of the present invention, the second predetermined current is specifically calculated by the following formula:

where, delta is a function of time,

t is a third preset duration for which δ is changed from 90 ° to 0 °.

In this embodiment, the second preset current is continuously changed according to time, so as to continuously adjust the input current of the permanent magnet synchronous motor until the switching time of the speed loop is determined by assuming the rotor flux angle and the rotor flux angle, thereby avoiding the situation that the rotor speed and the current of the permanent magnet synchronous motor are oscillated after switching, which is easy to occur in direct switching, and the starting failure occurs, and improving the starting probability.

Fig. 3 shows a schematic flow diagram of a motor control method based on a vector control system according to a further embodiment of the present invention.

As shown in fig. 3, a motor control method based on a vector control system according to still another embodiment of the present invention includes:

s302, when a speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining the first preset time;

s304, controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time;

s306, injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time;

s308, calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle;

s310, judging whether the angle difference value is in a first preset range, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In this embodiment, the angular difference between the assumed rotor flux linkage angle and the rotor flux linkage angle is calculated, and when the angular difference is within a first preset range, the time for switching the speed ring is considered to be in accordance with, the speed ring is controlled to be switched from open loop to closed loop, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated again in real time, and judging whether to control the process of switching the speed ring from open loop to closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, the assumed rotor flux linkage angle and the observed rotor flux linkage angle are limited within a certain range by setting a variation range of an angle difference value between the assumed rotor flux linkage angle and the rotor flux linkage angle and utilizing a first preset range, thereby reducing the conditions of rotor rotation speed and current oscillation in the switching process of the speed ring and starting failure, the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the first preset range.

Fig. 4 shows a schematic flow diagram of a motor control method based on a vector control system according to a further embodiment of the invention.

As shown in fig. 4, a motor control method based on a vector control system according to still another embodiment of the present invention includes:

s402, when a speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining a first preset time;

s404, controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time;

s406, injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time;

s408, calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle;

s410, performing low-pass filtering processing on the angle difference;

s412, performing angle compensation on the low-pass filtering processing result;

s414, judging whether the angle compensation result is in a second preset range, and controlling the speed ring to be switched from an open loop to a closed loop when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In the embodiment, an angle difference value of a supposed rotor flux linkage angle and a rotor flux linkage angle is calculated, low-pass filtering and angle compensation processing are carried out on the angle difference value, interference waveforms existing in the rotor flux linkage angle obtaining process are eliminated, meanwhile, angle compensation is utilized to process the low-pass filtering processing result, the problem that the angle deviation occurs after the calculation is finished, so that the additionally generated rotor rotating speed in the speed ring switching process and current oscillation in the switching process are caused, starting failure is caused, when the angle compensation result is in a second preset range, the time of switching according with the speed ring is considered, the speed ring is controlled to be switched from an open loop to a closed loop, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time again, and whether the speed ring is controlled to be switched from the open loop to the closed loop is judged according to the supposed rotor flux linkage angle and the rotor flux linkage angle, the change range of the angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle is set, the assumed rotor flux linkage angle and the rotor flux linkage angle obtained by observation are limited within a certain range by utilizing the second preset range, the rotor rotating speed and current oscillation in the speed ring switching process are reduced, the starting failure condition is generated, and the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the second preset range.

The first preset range and the second preset range are reasonably set according to the requirements of the permanent magnet synchronous motor, and preferably, the first preset range is smaller than the second preset range.

Fig. 5 shows a schematic flow diagram of a motor control method based on a vector control system according to a further embodiment of the invention.

As shown in fig. 5, a motor control method based on a vector control system according to still another embodiment of the present invention includes:

s502, when a speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining the first preset time;

s504, controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time;

s506, injecting second preset current into the q axis and the d axis, calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, obtaining the current of the d axis and the current of the q axis, outputting the current of the q axis to a PI controller of a speed ring, and outputting the current of the d axis to an id instruction controller of a current ring;

s508, calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle;

s510, performing low-pass filtering processing on the angle difference;

s512, angle compensation is carried out on the low-pass filtering processing result;

s514, judging whether the angle compensation result is in a second preset range, and controlling the speed ring to be switched from an open loop to a closed loop when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In the embodiment, when the rotor flux linkage angle of the permanent magnet synchronous motor is calculated, currents of a d axis and a q axis are obtained, the currents of the q axis are output to a PI controller of a speed ring, the currents of the q axis are output to an id instruction controller of a current ring, the current instructions when the speed ring is switched from an open loop to a closed loop are the same, and the situation that starting failure is caused by the fact that a difference exists between the current instructions before and after switching is avoided.

Fig. 6 shows a schematic flow diagram of a motor control method based on a vector control system according to yet another embodiment of the present invention.

As shown in fig. 6, a motor control method based on a vector control system according to still another embodiment of the present invention includes:

s602, when a speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining a first preset time;

s604, controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time;

s606, controlling a rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotating speed;

s608, injecting a second preset current into the q axis and the d axis, calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, acquiring currents of the d axis and the q axis, outputting the current of the q axis to a PI (proportional-integral) controller of a speed loop, and outputting the current of the d axis to an id (identity) instruction controller of a current loop;

s610, calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle;

s612, judging whether the angle difference value is in a first preset range, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In this embodiment, after controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotation speed according to a preset acceleration and operate for a second preset time, and calculating the assumed rotor flux linkage angle of the d-axis of the permanent magnet synchronous motor, before inputting a second preset current to the q-axis and the d-axis and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, controlling the rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotation speed to ensure that all parameter regions of the permanent magnet motor are stable at the preset rotation speed, avoiding an error caused by the calculation of the rotor flux linkage angle by the preset acceleration which still exists when the preset rotation speed is just reached, and further improving the observation precision of the rotor flux linkage angle.

In an embodiment of the present invention, preferably, the low-pass filtering processing on the angle difference is specifically calculated by the following formula:

wherein, theta_{err_lpf}For the angle difference after the low-pass filtering process, τ is the time constant of the low-pass filtering, s is the complex variable in the Laplace transform, and θ_errIs the angular difference without low pass filtering.

In this embodiment, the angle difference θ after the low-pass filtering process_{err_lpf}Directly passing through the time constant tau of the low-pass filtering, the complex variable s in the Laplace transform, the angular difference theta of the low-pass filtering_errAnd (4) calculating without complex technical process.

In an embodiment of the present invention, preferably, the angle compensation for the low-pass filtering processing result is specifically calculated by the following formula:

wherein, theta_{err_cri}For the angle compensation result, τ is the time constant of the low-pass filtering, T is a third preset time period for changing δ from 90 ° to 0 °, and θ_{err_lpf}Is the angle difference after the low-pass filtering process.

In this embodiment, the angle compensation result θ_{err_cri}A third preset time length T for changing the time constants tau and delta from 90 DEG to 0 DEG through low-pass filtering and the angle difference theta after the low-pass filtering processing_{err_lpf}The calculation is directly carried out, and a complex technical process is not needed.

Embodiments of a second aspect of the present invention provide a motor control system based on a vector control system, applied to a permanent magnet synchronous motor, wherein the vector control system at least comprises a speed loop and a current loop.

FIG. 7 shows a schematic block diagram of a motor control system 700 based on a vector control system according to one embodiment of the present invention.

As shown in fig. 7, a motor control system 700 based on a vector control system according to an embodiment of the present invention includes: a memory 702 for storing a computer program; a processor 704 for executing a computer program to: when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet synchronous motor and maintaining a first preset time; controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating a supposed rotor flux linkage angle of a d axis of the permanent magnet synchronous motor; injecting second preset current into the q axis and the d axis, and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time; and judging whether to control the speed ring to be switched from the open loop to the closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle.

In this embodiment, the processor 704 executes computer programs stored in the memory to: when the speed loop is opened, injecting a first preset current into a q axis of the permanent magnet motor, continuing for a first preset time, controlling a rotor of the permanent magnet synchronous motor to accelerate to a preset rotating speed according to a preset acceleration and operate for a second preset time, and calculating an assumed rotor flux linkage angle on a d axis while accelerating to the preset rotating speed; and injecting second preset current into the q axis and the d axis, calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, judging whether to control the speed ring to be switched from an open loop to a closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, judging the switching time of the speed ring by the assumed rotor flux linkage angle and the rotor flux linkage angle, avoiding the rotor speed and current oscillation of the permanent magnet synchronous motor after switching which is easy to occur in direct switching, and improving the starting probability due to the starting failure.

In one embodiment of the invention, the processor 704 is specifically configured to execute a computer program to: and calculating the assumed rotor flux linkage angle of the d axis of the permanent magnet synchronous motor according to the acceleration, the preset rotating speed and the second preset time.

In this embodiment, the processor 704 executes a computer program to obtain the assumed rotor flux linkage angle of the d-axis by integrating the acceleration to the preset rotation speed according to the preset acceleration for a second preset time period, wherein the second preset time period, the preset acceleration and the preset rotation speed are reasonably set according to the starting requirement of the permanent magnet synchronous motor.

In one embodiment of the invention, the processor 704 is specifically configured to execute a computer program to: the second preset current is calculated by the following formula:

where, delta is a function of time,

t is a third preset duration for which δ is changed from 90 ° to 0 °.

In this embodiment, the second preset current is continuously changed according to time, so as to continuously adjust the input current of the permanent magnet synchronous motor until the switching time of the speed loop determined by the assumed rotor flux angle and the assumed rotor flux angle is reached, thereby avoiding the situation that the direct switching is easy to occur, the rotor rotation speed of the permanent magnet synchronous motor after switching is output, the current oscillation in the switching process occurs, the starting failure occurs, and the starting probability is improved.

In one embodiment of the invention, the processor 704 is specifically configured to execute a computer program to: calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle; judging whether the angle difference value is in a first preset range, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In this embodiment, the angular difference between the assumed rotor flux linkage angle and the rotor flux linkage angle is calculated, and when the angular difference is within a first preset range, the time for switching the speed ring is considered to be in accordance with, the speed ring is controlled to be switched from open loop to closed loop, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated again in real time, and judging whether to control the process of switching the speed ring from open loop to closed loop according to the assumed rotor flux linkage angle and the rotor flux linkage angle, the assumed rotor flux linkage angle and the observed rotor flux linkage angle are limited within a certain range by setting a variation range of an angle difference value between the assumed rotor flux linkage angle and the rotor flux linkage angle and utilizing a first preset range, thereby reducing the conditions of output speed rotor rotation speed in the switching process of the speed ring and current oscillation in the switching process and starting failure, the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the first preset range.

In one embodiment of the invention, the processor 704 is specifically configured to execute a computer program to: calculating an angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle; carrying out low-pass filtering processing on the angle difference; carrying out angle compensation on the low-pass filtering processing result; judging whether the angle compensation result is in a second preset range or not, and controlling the speed ring to be switched from an open ring to a closed ring when the judgment result is yes; otherwise, repeating the step of calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time.

In the embodiment, an angle difference value of a supposed rotor flux linkage angle and a rotor flux linkage angle is calculated, low-pass filtering and angle compensation processing are carried out on the angle difference value, interference waveforms existing in the rotor flux linkage angle obtaining process are eliminated, meanwhile, angle compensation is utilized to process the low-pass filtering processing result, the problem that the angle deviation occurs after the calculation is finished, so that the additionally generated rotor rotating speed in the speed ring switching process and current oscillation in the switching process are caused, starting failure is caused, when the angle compensation result is in a second preset range, the time of switching according with the speed ring is considered, the speed ring is controlled to be switched from an open loop to a closed loop, otherwise, the rotor flux linkage angle of the permanent magnet synchronous motor is calculated in real time again, and whether the speed ring is controlled to be switched from the open loop to the closed loop is judged according to the supposed rotor flux linkage angle and the rotor flux linkage angle, the change range of the angle difference value of the assumed rotor flux linkage angle and the rotor flux linkage angle is set, the assumed rotor flux linkage angle and the rotor flux linkage angle obtained by observation are limited within a certain range by utilizing the second preset range, the output speed rotor rotating speed in the speed ring switching process and the current oscillation in the switching process are further reduced, the starting failure condition occurs, and the starting probability of the permanent magnet synchronous motor can be effectively improved by setting the second preset range.

The first preset range and the second preset range are reasonably set according to the requirements of the permanent magnet synchronous motor, and preferably, the first preset range is smaller than the second preset range.

In one embodiment of the invention, the processor 704 is further configured to execute a computer program to: and acquiring the current of the d axis and the current of the q axis, outputting the current of the q axis to a PI controller of a speed loop, and outputting the current of the q axis to an id instruction controller of a current loop.

In the embodiment, when the rotor flux linkage angle of the permanent magnet synchronous motor is calculated, currents of a d axis and a q axis are obtained, the currents of the q axis are output to a PI controller of a speed ring, the currents of the q axis are output to an id instruction controller of a current ring, the current instructions when the speed ring is switched from an open loop to a closed loop are the same, and the situation that starting failure is caused by the fact that a difference exists between the current instructions before and after switching is avoided.

In one embodiment of the invention, the processor 704 is further configured to execute a computer program to: and controlling the rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotating speed.

In this embodiment, after controlling the rotor of the permanent magnet synchronous motor to accelerate to a preset rotation speed according to a preset acceleration and operate for a second preset time, and calculating the assumed rotor flux linkage angle of the d-axis of the permanent magnet synchronous motor, before inputting a second preset current to the q-axis and the d-axis and calculating the rotor flux linkage angle of the permanent magnet synchronous motor in real time, controlling the rotor of the permanent magnet synchronous motor to operate for a fourth preset time according to the preset rotation speed to ensure that all parameter regions of the permanent magnet motor are stable at the preset rotation speed, avoiding an error caused by the calculation of the rotor flux linkage angle by the preset acceleration which still exists when the preset rotation speed is just reached, and further improving the observation precision of the rotor flux linkage angle.

In an embodiment of the present invention, the low-pass filtering processing on the angle difference is specifically calculated by the following formula:

wherein, theta_{err_lpf}For the angle difference after the low-pass filtering process, τ is the time constant of the low-pass filtering, s is the complex variable in the Laplace transform, and θ_errIs the angular difference without low pass filtering.

In this embodiment, the angle difference θ after the low-pass filtering process_{err_lpf}Directly passing through the time constant tau of the low-pass filtering, the complex variable s in the Laplace transform, the angular difference theta of the low-pass filtering_errAnd (4) calculating without complex technical process.

In an embodiment of the present invention, the angle compensation for the low-pass filtering processing result is specifically calculated by the following formula:

wherein, theta_{err_cri}For the angle compensation result, τ is the time constant of the low-pass filtering, T is a third preset time period for changing δ from 90 ° to 0 °, and θ_{err_lpf}Is the angle difference after the low-pass filtering process.

In this embodiment, the angle compensation result θ_{err_cri}A third preset time length T for changing the time constants tau and delta from 90 DEG to 0 DEG through low-pass filtering and the angle difference theta after the low-pass filtering processing_{err_lpf}The calculation is directly carried out, and a complex technical process is not needed.

An embodiment of the third aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method according to any of the above-mentioned claims.

In the computer-readable storage medium provided by the present invention, when being executed by a processor, the computer program stored thereon can implement the steps of the method according to any of the above technical solutions, so that the method has all the beneficial technical effects of the above motor control method based on the vector control system, and details are not repeated herein.

Fig. 8 shows a schematic flow diagram of a motor control method based on a vector control system according to yet another embodiment of the present invention.

Fig. 9 shows a motor control block diagram based on a vector control system in an embodiment of the invention.

FIG. 10 is a diagram illustrating a frequency, a first predetermined current, a second predetermined current, and an angle difference according to an embodiment of the present invention.

As shown in fig. 8, the motor control method based on the vector control system includes:

s1: speed loop bypass and current loop closed loop, as shown in FIG. 9, all 3 switches in the figure are placed at position 1, and current command i is given on q-axis_opSin δ, δ being 90 ° and held for 1 second, as shown in stage t1 in fig. 10, and then jumping to S2;

s2: slowly accelerating to a designated speed, as shown in the stage t2 in FIG. 10, at which the assumed rotor flux linkage angle θ is_opObtained by integrating the speed command, as shown in fig. 10, and then jumps to S3;

s3: the speed is maintained for 1 second, as shown in the t3 stage of fig. 10, and then a jump is made to S4;

s4: q-axis given current command i_opSin delta, d axis given current command i_opCos δ, δ in accordance withAs shown in stage t4 of fig. 10, it should be noted that in the subsequent link S8, when the condition is not met, the step needs to be returned to continue the change of δ;

s5: operating the rotor flux linkage angle theta while the above steps are being performed_obsCalculating;

s6: while the steps are carried out, feeding back the d/q axis current instruction to a speed loop for output;

s7: the rotor flux linkage angle θ will be assumed_opMinus the observation angle theta_obsTo obtain the angle difference theta_errAnd is processed by the following steps:

(1) a first-order low-pass filtering is performed,

(2) the compensation is carried out by the computer system,

finally theta_{err_cri}As a criterion angle difference;

s8: when theta is_{err_cri}Satisfies the condition that theta is less than-1 DEG_{err_cri}If the angle is less than 1 degree, the process goes to S9;

s9: the speed loop switches from bypass to closed loop, switching the respective switch to position 2 in fig. 9.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.